Ultrasonic cleaner



New. 7, 1961 c. G. LEONHARDT ET Al. 3,007, 8

ULTRASONIC CLEANER Filed April 15, 1958 5 Sheets-Sheet l INVENTORS.MELEfi C LEON/4,4207 BE/A V E. BALDW/A/ M 47 oeA/fys NW. 1951 c. G.LEONHARDT ETAL 3,807,47

ULTRASONIC CLEANER 5 Sheets--Sh'eet 2 Filed April 15, 1958 w mMw m O W Em N E EL 2 A w w W M M 5 MM m .1.

New, 7, 1961 c. e. LEONHARDT ET AL fl flm ULTRASONIC CLEANER Filed April15, 1958 5 Sheets-Sheet s SEE \m QQQU QM 1961 c. G. LEONHARDT ET Al.3,007,47

ULTRASONIC CLEANER 5 Sheets-Sheet 4 Filed April 15, 1958 mu QQINVENTORS. c/muzs q Mom/14 207 512/4 5. 5AA DW/A/ United States PatentOfi" 3,007,478 Patented Nov. 7, 1 9,61

3,007,478 I ULTRASONIC CLEANER Charles G. Leonhardt, Huntington, N.Y.,and Brian E. Baldwin, Evanston, 111.; said Leonhardt assignor to'Acoustica Associates, Inc., Mineola, N.Y., and said Baldwin assignor toAmerican Hospital Supply Corporation, Evanston, 111., a corporation ofIllinois Filed Apr. 15, 1958, Ser. No. 728,667 17 Claims. (Cl. 134-57)This invention relates to cleaners, and more particularly to afully-automatic ultrasonic cleaner.

The primary object of the present invention is to generally improveultrasonic cleaners. A more particular object is to provide anultrasonic cleaner which is completely automatic, for which purpose itemploys a clock timer and level switches to establish a desired programof washing and rinsing. A more specific object isto provide such acleaner for hospital and surgical use, for the cleaning of medical andsurgical instruments. Still another object is to provide such a cleanerwhich acts additionally as a sterilizer for the medical instruments.

To accomplish the foregoing general objects, and other more specificobjects which will hereinafter appear, our invention resides in theultrasonic cleaner elements, and their relation to one another, as arehereinafter more particularly described in the following specification.The specification is accompanied by drawings in which;

FIG. 1 is a perspective view of one part of an ultrasonic cleanerembodying features of my invention;

FIG. 2 is a schematic transverse section. through the cleaner;

FIG. 2a schematically represents a basket which may be loaded withinstruments and inserted in the tank;

FIG. 3 is an elevation of a combined cover and spray head;

FIG. 4 is a bottom view of the same; I

FIG. 5 shows the relation of a group of, level switches to the tank; 7

FIG. 6 is a fragmentary view corresponding to a part of FIG. 2, butshowing -a modification which provides sterilizing as well as cleaning;

FIG. 7 is a plan view of a part of the modified cleaner, showing clampsapplied to the cover;

FIG. 8 is a side elevation of one of the clamps, drawn to enlargedscale;

FIG. 9 is a highly schematic diagram explanatory of the flow circuit,for both water and electricity;

FIG. 10 is. a wiring diagram showing the electrical circuitry;

FIG. 11 is a fragmentary diagram explanatory of a part of the timing ofthe cams in the clock timer; and

'FIG. 12 shows the complete timing to much smaller scale, and comparesthe timing with and without sterilization.

Referring to the drawings, and more particularly to FIG. 2, theultrasonic cleaner comprises a tank 12, having a transducer 14 at thebottom of the tank. This is driven at a suitable ultrasonic frequency,for example, twentyfive kilocycles per second, by an ultrasonicgenerator not shown here. The transducer and generator may beconventional, and require no detailed description.

There is a Water inlet at the top of the tank, shown at 16 in FIGS. 1and 2, and a drain 18 at the bottom of the tank. For convenience, thearticles to be cleaned, in this case medical and surgical instruments,may be loaded in a basket shown at 20 in FIG. 2a, and the said basket islowered into the tank. The basket preferably has feet 19, and handles21. It is drawn to reduced scale in FIG. 2a, and in practice may fit thetank. At the end of the cleaning operation, the basket is removed withthe instruments.

The circuitry further includes one or more water level switchesconnected to the tank, and in FIG. 2, there are three level switches 31,32 and 33. These may all be connected to a common point on the tank,indicated at 24, and the connection point is preferably well down, saysix inches from the bottom. The arrangement of level switches is bettershown in FIG..S, which shows how switches 31, 32 and 33 are connectedbypipes to a common connection point 24 on the tank 12. It may bementioned that the desired operation could be controlled with a singlelevel switch, the others being a refinement, as is explained later, Thelevel switch is also called a pressure switch, because it responds tothe pressure of the water on its reaching a predetermined level.

The tank 12 is concealed within a generally flat sided housing structuresomewhat resembling an automatic clothes washer or dishwasher or likeappliance, and in the present case, the tank is located at the left endof the housing, while the ultrasonic generator occupies the right end ofthe housing. The housing may be backed against a wall, as indicated at26 in FIG. 2, and has permanent plumbing connections, in this case, ahot water line 28, a cold water line 30, and a drain 34. Hot and coldwater are mixed, in a mixer valve assembly 36 to,

produce water of desired temperature under thermostat control, whichthen flows through pipe 38 to a vacuum breaker 40, and thence throughpipe 42 to a check valve for removal from the top of the tank, as wheninserting or removing the basket 20. Most conveniently, the spray ring46 is secured directly beneath and forms a part of a cover 48 for thetank, and the use of a flexible hosefor the water supply is avoided -byfeeding the water si1pply through the hinge. More specifically,referring to FIG. 1, the cover 48 is carried by a bent pipe 50 supported between elbow couplings 52, 54 with packing nuts at 56. The watersupply is connected to either the elbow 52 or 54, as shown at 58 in FIG.2.. The construction of the spray head is also shown in FIGS. 3 and 4,thespray ring 46 being secured beneath cover 48, and hav ing a ring ofspray holes 60. The water connection to ring 46 is indicated at 16. Thehinge action and the open position of the cover and spray head, out ofthe way of the top of the tank, are shown in FIG. 6.

Reverting to FIG. 2, the drain connection 18 could be a gravity drain,but there are important advantages in using a drain pump, and in thepresent case, drain 18 leads through pipe 62 to a pump 64, which may beof the centrifugal type, and the discharge of which flows upward throughpipe 66, and a check valve 68' to a valve check acting as a vacuumbreaker 70, and thence -downward through pipe 72, to a trap 74 and drainpipe 34.

or vacuum breaker 40, and the check valve 44, are requirer'nents of thesanitary code in many communities, in order to prevent any possibilityof backed up sewage entering the fresh water supply.

One advantage of the drain pump 64 is that the pump itself may be usedunder electrical control to time the draining of the tank. The pump maybe an open pump, with free fiow ther'ethrough, but there is no drainageexcept when the pump operates because of the piping to the high point70, which is at a level higher than the liquid level in the tank.Another advantage-of the pump 64 is that the drain piping may besmaller. In the present case, the tank is an eight-gallon tank, aboutten inches in diameter and twenty inches high, yet it may be rapidlydrained while using one inch piping at 62, 66, 72, and 74, and althoughleading into a conventional two-inch waste line 34, which latter is thesize of pipe that would be required without the pump.

In FIG. 1, attention is directed to push button 76. This is apreliminary start button which is pressed before beginning operation ofthe machine, and which serves to supply heater current to the cathodesof the main vacuum tubes of the oscillator. It is customary anddesirable to warm the vacuum tube cathodes before applying the highplate voltage, and the latter is not applied'until after the machine isactually started. This actual start of the machine is obtained byturning the dial 22 away from its oil position, as previously mentioned.The part 78 is a pilot lamp which lights whenever the button 76 has beenpressed to heat the cathodes. This start button 76 is of the type calledpush on-push off, meaning that when pushed, the circuit stays on, andwhen pushed again, the circuit remains off. The only indication that theheater circuit is on is the pilot lamp 78. The dial 80 is a temperatureselector dial. In the present case, this provides two temperatures. Onetemperature is that of the hot water supply available in the building,which may be from one hundred forty degrees to one hundred eightydegrees Fahrenheit. This may be used for the cleaning of ordinaryarticles. The other temperature is a substantially lower temperature,say one hundred five degrees Fahrenheit, and this is used in hospitalsfor the cleaning of surgical instruments, because the higher temperaturetends to set blood, pus, etc.

Referring now to FIG. 2, the cold water line 30 is tapped by a pipe 82which supplies cooling water to the water jacket of transducer 14. Theflow of cooling water is controlled by a solenoid operated valve 84, andleads into the water jacket at 86. The cooling water is discharged at88, and the existence of an actual flow of cooling water is detected bya flow detecting device indicated at 90, the purpose of which isexplained later. The cooling water then flows upward through pipe 92,and possible back pressure in the transducer jacket is avoided by anopen spout 93 and funnel 94. The discharged cooling water flowsgravitationally through pipe 96 to the trap 74. A check valve 98 isprovided in line 96 to counteract any pressure developed by the drainpump 64, and is anyway desirable in the event of backing up of the wasteline 34.

Referring now to FIG. 9, the cold water line is indicatedin the upperleft corner at 30, the hot water line at 28, their mixing valve at 36,the waste line in the lower right corner at 72, and the transducercooling water waste line at 92, 96. The tank 12, with its transducer 14,shower inlet 46, and drain pump 64 are also shown schematically. Thethree level switches are indicated at 31,

32-and 33, and are connected to the tank at the point 24 by pipes 100and 102. The cooling water for the transducer is, supplied through pipe82 (top of diagram) and solenoid valve 84 to the jacket at 86, andleaves at 88 through'pipe 92 and flow switch or flow detector 90. Thestart button for heating the vacuum tubes is shown at 76 (lower leftpart of the diagram), and supplies current to a filament transformer104, and also to the flow detector switch 90. However, the oscillator,indicated at 106, does not start until energized by closing of fiowdetector switch 90, as indicated here by the connection 108. This is asafety interlock which insures that power will not be supplied to thetransducer 14 unless it first is supplied with cooling water, and thecontinued operation of the oscillator 106 is dependent at all times onthe continued flow of cooling water, as detected by the flow switch 90.

The timer or clock motor is shown at 110. It drives a cam shaft 112carrying a series of cams which operate switches. The dial of the timeris shown at 22, and by turning this slightly away from its off position,a cam T114 closes a switch to supply current through line 116 to thetimer motor 110 if relay K2 is energized, or if relay K1 isde-energized. It also supplies current to timer switches T130, T132, andT142, as shown at 115.

In addition there is a supply of current through line 118 and 122 to thesolenoid valve 84 which controls the flow of cooling water through pipe82 to the transducer jacket. This in turn starts the oscillator 106because the flow of cooling water closes the fiow switch 90 and suppliescurrent to oscillator 106.

Before describing the operation in detail, it may be well to refer tothe wiring diagram shown in FIG. 10. This is an across the line diagram,with the switching performed in the upper line L1, and with a groundreturn shown by the lower line L 2. The element 124 is simply aninterlock controlled by the front panel of the cleaner, in order tode-energize all of the circuitry if the front panel is removed. This isdone because of the high voltages used in the oscillator. A fuse isshown at 126, and a start button at 76, which remains closed, it being apush start push stop button. When the button is pressed, the pilot lamp78 is lighted, and current is supplied to the filament heating circuitof the oscillator, indicated at 104.

To further start the cleaner, the clock dial is turned away from offposition thereby causing a cam to close timer switch T114 leadingthrough line 118 to the solenoid of solenoid valve 84, which causes aflow of cooling water to the transducer. That flow closes the flowdetector switch 90, thereby starting the ultrasonic generator 106 byputting high voltage on the plates of the previously warmed tubes.Additional timer switches are shown in generally upright position, andare prefixed by the letter T. The three level switches are shown ingenerally horizontal position at 31, 32, and 33. The temperatureselecting dial and its switch are shown at 80. The timer motor is shownat 110, and the drain pump motor at 64.

The mixer valve is indicated at 36, and it may be explained at thispoint that it comprises two solenoid valves and a thermostat. It is soconstructed as to receive? three pipe connections, two coming in withhot and cold water, and one leaving with mixed water. It alsoreceivesonly two electrical connections, here symboiiziedi as leading to twosolenoids 37 and 39, but the internai construction is not simply twoseparate solenoid valves operating hot and cold lines. When the hotwater solenoid is connected, there is an on and off control of hot wateralone. When the warm water solenoid is connected, there is an on and offcontrol of warm water, the Warmth of which depends on a thermostataction which admits and mixes cold water with the hot water inappropriate amounts. When the temperature selector switch is moved tohot, the circuit is closed to contact 81, for on and off control of hotwater, and when selector 80 is moved to warm, the circuit is closed tocontact 83, for on and off control of warm water. In this case, the flowis further controlled by a thermostat, not shown, When there is to be noflow of water, both circuits are de-energized, and this may be done byopen: ing of level switch 31 or 33. However, with the level s i s e heow f w er is co tro d by t e.

timer, as indicated for example by the timer switches T130 and T132.

There is a relay K1 which has one pair of contacts, which are normallyclosed, as shown at 136. There is another relay K2 which has normallyopen contacts K2A controlling the drain pump motor 64, and K213 shuntingthe contacts 136.

Operation At the beginning, the timer is in o position, and pressure onpush button 76 (FIGS. 9 and 10) turns on the pilot light 78, and heatsthe tube filament circuit indicate-d at 104.

Before or after pressing the start button 76, the basketful ofinstruments is placed in the tank, a quantity of detergent is added, saythree ounces, and the cover is closed. At any time during thispreliminary period, before or after loading the tank, the temperaturedial 80 is properly set. If the cleaner is being used continuously forsurgical instruments, this dial will simply remain in the warm (onehundred and five degree Fahrenheit) position.

The timer dial is then turned from off into the was cycle. Without thesterilization referred to later, the cleaning operation takes less thanfifteen minutes, and a fifteen-minute clock may be used, that is, onewhich turns one full revolution in fifteen minutes. Most of this isavailable for the wash cycle, but less than all of the available washcycle may be used by simply turning the dial further into the washcycle. In the particular case here illustrated the maximum washing timeis 10.4 minutes, but this may be cut down to anything less, if desired,by simply turning the dial as far as desired along thewash cycle.

In any case, movement of the timer from off position starts the flow ofcooling water to the transducer through the action of cam T114 andconductors .116, 118, and 122, energizing cooling water solenoid valve84. The resulting flow of cooling water closes detector switch 90, andstarts the ultrasonic generator 106, whereupon the transducer isenergized. Meanwhile, water of appropriate temperature is sprayed intothe tank by opening of one or both solenoid valves of the mixing valve,and for this purpose, clock switch T130 is closed. thereby supplyingenergy to the mixer valve, it being kept in mind that the level switches31 and 33 are closed at this time, and remain closed until the tank isfull. Also clock switch T144 is closed. In FIG. 9 the circuit is throughlevel switches 31 and 33 and conductors 133 and 135.

Relay K1 has normally closed contacts 136, However, at this time, thelevel switch 32 is closed to its lower contact, thereby energizing thesolenoid of relay K1, and thus opening the contacts 136-, and becausecontacts 136 are open, the timer motor 110 does not run. In general, thetimer motor is de-energized during filling of the tank, and is energizedduring washing, and during pants of the rinsing cycles. The relay K2 isenergized whenever the drain pump motor operates, because it controlsthe drain pump motor through its contacts-KZA, and therefore thecontacts K213 also close whenever the drain pump motor operates. Theseshunt the contacts K1 even when the latter are open. Relay K1 opensduring filling, and the timer motor stops unless the tank is alsodraining, in which case the timer motor runs because of closing ofcontacts K2B.

Thus turning the time dial to any position in the approximately tenminute long wash cycle causes ultrasonic energy to be presented to thetank through energizing of the cooling solenoid, and causes water tospray into the tank, since the fill contact T130 closes and level switch31 is closed in its relaxed condition. The temperature switch 80 selectseither the warm or the hot input, causing warm or hot water to flow.Level switch 32 is closed to its lower contact, thus energizing relay s6 K1, and so opening contacts 136 and thereby opening the line to thetimermotor 110.

It will be noted that the transducer is operating during filling of thetank. This is a significant feature of the invention, because it hasbeen found that this provides rapid degassing of the water. Theultrasonic cleaning action is weakened by gas content in the water. Ifthe tankwere first filled before starting vibration, it would take somefifteen or twenty minutes to degas the water. (Without vibration itwould take many hours.) However, by providing transducer vibrationduring the filling of the tank, the water is degassed in a matter ofonly two minutes, one of which is anyway occupied by filling of thetank, so that for allpractical purposes, the water is degassed in oneadditional minute. The tank is filled to a height established by levelswitch 31, which in the present case. is four inches from the top of thetank. Timer motor will not run until level switch 31 has been trippedopen, and relay K1 is thereby de-energized. When the tank has beenfilled to the said first level, the mixer valve and the relay arede-energized, shutting off input water at mixer 36 and beginningoperation of timer motor 110. Motor operation will not be interrupted,and the water level remains constant, throughout wash" interval. I

At the end Tlittlopens and the timer drain contact T142 closes. Thisenergizes therelay K2 and so the drain 64, and therefore the tankempties.

The complete rinse action of the present cleaner may be divided into twomain parts. The first may' be referred'to-as a fluctuating-level rinse,which is provided bya continuous inlet or spray rinse accompanied by anintermittent drain,with the drain at a faster rate than the. sprayinlet. Thus, there is a continuous spray action, but the level in thetank changes from partly empty to full, and this may be donerepeatedlyfor a number of fluctuations determined "by the timer clock,as explained later. In the present case there are three fluctuations.

It has been found that the use of a large distributed spray is highlypreferable tomere filling through an inlet at the side or top of thebank, because the spray helps remove any clinging residue of skin on theinstruments during draining. These tend to cling, but by using a sprayfilling or rinsing action during actual bulk drainage ofliquid fromthe'tank, the clinging of skin to the instruments has been reduced bysome ninety percent. Moreover, a side watenconneotion to the tank, forexample like that shown for steam at 244 in FIG. 6, creates a vortexwhich reduces the efficiency of ultrasonic cleaning. It would also failto have the downward and widely distributed spray for the removal ofclinging particles, as does the spray head, which sprays downwardly overthe entire basket.

Because the pump drainageis much faster than the spray inlet, the tankis largely, say half or more emptied, in about thirty seconds, whereuponthe pump stops, and the continued spray fills the tank again. Thefilling dur-v ing this fluctuating spray is to a point three inches fromthe top of the tank, as determined by the level switch 32. The levelswitches 31 and 32 are set an inch apart in height not only for desiredliquid level, but also to make certain that there is no interference intheir operation. It would not do to have level switch 32 trip,

when only level switch 31 is supposed to, because then there would bedrainage of water and detergent during It is found that a one inchdifierence overflow in the event of failure of drainage, or failure ofeither level switch 31 or 32. Thus, in FIG. 10, it will be seenthatopening of level switch 33 will de-energize the mixer valve circuit, andso prevent further filling.

Level switch 32, unlike the others, is used in a differof the was cycle,the timer fill contact pump motor 7 ential way, that is, it has twocontacts as shown in FIG. I0, the upper of which is closed when thepressure exerted thereon indicates a water level three inches from the;top of the tank, and-the lower of which is connected to the relay coilK1. The upper contact leads to the coil of relay K2, and during thefluctuating rinse period, the; motor 64 is started each time the tank isfull. It is stopped when the level switch opens at its upper contact,and this is a diflferential or delayed action which does not take placeuntil the water level has dropped a substantial amount, which in thepresent case is some eight inches.

Afifi i about thirty seconds, the timer rinse contact T132, closes.Drain continues while water sprays into the tank. The timer continues torun though relay K1 the relay K1 is de-energized, causing closing ofcontacts- 136 which causes the timer motor 110 to run. Level switch32also energizesrelay- K2 and causes the, drain pump 64 to come on, whilewater continues to spray into the tank. The draining, action, isconsiderably faster than thefilling, and the water level will dropthrough the ditferential distance of the levelswitch 32. At the. lowerlevel, approximately eight inches below the actuating height, the levelswitch 32 returns to its relaxed position.

Drain pump 64 and timer motor 110. stop until the water level rises toproduce the same cycling over again.

It will thus be seen that the medical andsurgical in-- struments arehere subjectedto what is here termed'a fluctuating-level rinse, therinsingaction being continuous, but the level of water in the tank beingcyclically variedbetween a height of, say nine inches, and a height ofsay seventeen inches. One important advantage of the fluctuating-levelrinse isthat it avoids what mightbe termed dead spots, that is, spots.where the ultrasonic activity is weak. By moving the liquid level up anddown, different loads are put on the transducer, and the regions ofmaximum and minimum ultrasonic activity v and consequent cavitation aremoved around or changed, so that ,at one time or another, there isstrong activity in every part of the tank.

It is importantto understand that the transducer is kept operatingthroughout the washing and rinsing cycles, and indeedLits operation iscontinuous. Thus, there is cavitation, and cleaning of any residual bitsof skin from the instruments by the body of warm water in the tank,apart from the falling spray action. When the tank is partly emptied,the lower region is subjected to ultrasonic cleaning, andthe upperregion to spray action. Thus, considerable overall cleaning time issaved by continuously spraying during the filling and draining of thetank, and by continuing the ultra-sonic vibration during the filling anddraing of the tank.

The timer motor runs whenever the drain motor runs. Thus, during thefluctuating-level rinse, the timer motor runs during drain, even thoughdraining and stop page of drain is controlled by the level switch 32.The time of drain is known, it being, say one and one-half second perinch, and thus the clock cam may be set to terminate thefluctuating-level rinse after a desired number of fluctuations, saythree in the present case.

After three cycles of raising and lowering of the level, the timer draincontacts 142,close, causing the tank to empty while water still spraysin, and keeping the timer motor 110 running. Also at this time the timerswitch 144 moves to the hot contact, so that the ensuing final Relay K2opens and therefore the 8 rinse is with hot water. After thirty seconds,the timer rinse contact 132 opens.

Timer drain contact 142 remains closed for fifteen seconds to insurecompletely evacuating the liquid in the tank, the latter being onlyabout half full.

Following this final drain period, the timer on-off contact T114 opens,interrupting the power to all of the timer controlled circuits, andshutting off the generator circuit through the cooling water solenoidvalve 84. The generator vacuum tube filaments remain heated until themain switch button 76 is pushed, this being a push on push ofi switch.The pilot lamp shows the need for this final shut down, assuming thereare no further batches of instruments waiting to be cleaned.

Timer and circuitry FIG. 11 shows a part of the timer cam operation,drawn to enlarged scale. Without sterilization, the timer duration maybe say fifteen minutes, which is represented at 270in FIG. 12, while theportion shown in the dotted rectangle 274 corresponds generally to whatis shown in enlarged scale in FIG. 11. In general, when the cam is showndown, its switch is closed, and when the cam is shown up, its switch isopen. Thus, the timer switch T114 is closed throughout the cycle, assoon as the dial is turned away from the ofF position, and the oifposition is indicated at 300 at the end of the cycle. All camsare raisedat this point, so that all switches are open, and it corresponds to therest or off position of the timer dial.

The timer cam T is closed for most of the cycle, but opens and remainsopen at the point 302. The timer switch T144 provides hot water for thefinal rinse, and this switchis therefore open most of the time. Itcloses at the point'304, which marks the beginning of the second or hotwater rinse.

The timer drain switch T142 isopen at 306, closed at 308, open at 310,and closed at 312. However, as will be seen by referring to FIG. 10,this does not constitute the only supply of power for relay K2 and thedrain pump, and the relay also may be energized through level switch 32during the period that timer switch T130 and level switch 31 are closed,and also during the period that timer switch T132 is closed. This takeseffect dur' ing the fluctuating-level rinse.

Timer switch 132 is for the both rinses. It differs from timer switch144, which controls the water temperature, whereas timer switch 132controls the flow operation of the mixing valve. The power supply isindicated to be on at 318, which corresponds to both thefluctuating-level rinse, and the hot rinse.

Referring now to FIG. 9, the timer cams are schematically indicated atthe left of the diagram, and the numbers correspond to the numberspreviously used in FIGS. 10 and 11. In FIG. 9, an additional cam 262 isshown, which has to do with sterilization, as is explained later.

The timer has been simplified, and omits the switches at most of thecams. For this reason cams T144 and T114 are shown as though made ofinsulation. It will be seen that the conductor from cam 130 leads to thelevel switch 31, as it does in FIG. 10; that the earn 132 leads to levelswitches 32 and 33, and indirectly to the level switch 31, as it does inFIG. 10; and that the cam 142 leads to the level switch 32 and to thecoil of relay K2, as it does in FIG. 10. The cam 114 closes a circuitfrom the push button start switch 76 and runs as though to the othertimer switches at 115, and to valve 84 at 116, 118, and 122. The cam 144closes a switch leading from level switch 33 to water temperaturecontrol 80, also as in FIG. 10.

Sterilization The final rinse is with hot water, regardless of thesetting of the temperature selector, and this is so because of theaction of the clock timer switch T144 located in FIG. 10 ab v t p tureselector 80, f th a er is not arranged for sterilization, theinstruments then simply dry in the machine, which for all practicalpurposes is shut down. The hot final rinse assists rapid dry.

However, by some modification, the machine may be used to providesterilization. Referring to FIG. 6, a steam line 242 is connected to thetank at 244, and the supply of steam is controlled by a solenoidoperated valve 246. An additional solenoid operated valve 248 isinserted in the water line 58 leading to the spray head 46. A thirdsolenoid operated valve 250 is inserted in the drain line 62. The cover48 is preferably proviedd with a peripheral gasket 49. Y

Referring now to FIG. 7, the cleaner is provided with a suitable coverlocking means, here illustrated by a pair of clamps 252 pivoted at 254.The nature of these clamps will be clear from inspection of ,FIG. 8, inwhich it will be seen that the working end 256 of the clamp preferablyslopes on bottom to provide a camming or wedge action.

Referring now to FIG. 9, the steam line is shown at 242. A pressureregulating or reducing valve 258 may be provided if the steam supply isat too high a pressure. The three added solenoid valves are indicated at246, 248 and 250. The steam valve 246 is normally closed while thevalves 2-48 and 250 are normally open. In'such case, all of thesolenoids may be connected together to a common line 260 which leads toan additional cam switch T262 on the timer clock. It will be evidentthat if switch 262 is energized at the end of the washing and rinsingcycles, steam will be admitted to the tank 12 to sterilize theinstruments. The steam will be held under pressure by the closing of thevalves 246 and 250, and the clamp ing of the cover. Sterilizationis'ordinarily carried out at a temperature of about two hundred fiftydegrees Fahrenheit, by using steam pressure of about thirty pounds persquare inch. This is carried out for a period of say one half hour,valthough some may prefer less and others more time.

'In FIG. 10, the added timer switch 262 is shown at the right, andcontrols all three solenoid valves 246, 248 and 250. I

Referring now to FIG. 12 of the drawing, this com pares the cleaningcycle without sterilization, shown at 270, 'and the cleaning cycle withsterilization, shown at 272. The cycle shown at 270 is about fifteenminutes long, with about ten minutes devoted to washing. The dottedrectangle 274 corresponds substantially to what is shown to much largerscale in FIG. l-l.

In the cycle shown at 272, the same ten minute wash period is provided,followed by the same rinsing cycle shown in dotted lines at 276, whichagain corresponds to what is shown in detail in FIG. ll. This isfollowed by a sterilizing period which, as here illustrated, is aboutone half hour long. The clock timer used in this case is a three-quarterhour clock, thus providing the desired additional one half hour time forsterilization. At the end of this time, the clock switch T262 in FIG. 9opens; the steam valve 246 is closed, and the sealing valves'248 and 250are opened, thus restoring the machine to its off condition.

A one hour clock may be used, and the sterilizing time may be pushedahead for less time, or a separate adjustment of sterilizing time may beprovided. Some doctors believe a much shorter sterilizing time isadequate.

Miscellaneous In FIG. 10, the dial .22 is shown connected to contacts23. It may be explained that the clock timer is so 1 said generator andwater level switch, and providing a ventional clock motors, which arealready commercially available on the market. In the present case, theclock timer is made by BaysideTimers of Bayside, Long Island,

New York. It comprises steel cams working on microswitches. A similarlyusable timer is made by Hayes Manufacturing Company of Wisconsin.

'The level switches here used are Type No. 18355 made by BendixCorporation of Cincinnati, Ohio. They may also be Type No. 1466318 madeby Westinghouse Electric Company at Mansfield, Ohio. The flow switchwhich interlocks the cooling water of the transducer with the operationof the ultrasonic generator, is that known commerci-ally as Shur Flowmade by Hayes Manufacturing Company of Erie, Pennsylvania, but otherflow switches are commercially available.

It will be understood that while we have shown three level switches,only one would be essential, in which case a single tank level would beused for both washing and for the fluctuating rinse, instead of the twoslightly. different levels here employed. The use of a second levelswitch simplifies the circuitry. The third level switch is merely forsafety.

"It will be understood that the transducer may be conventional, and maybe of the magnetostrictive type, or the piezoelectric type using bariumtitanate ceramic. The ultrasonic generator also may be conventional, andrequires no detailed description.

Suit-able transducers and generators may be obtained from AcousticaAssociates, Inc. of Mineola, Long Island, New York.

High temperature water would be used throughout the cleaning operation,instead of only for the final rinse when cleaning articles other thanbloody medical instruments.

etc. have already been washed away.

It is believed that the construction and operation of our improvedultrasonic cleaner, as Well as the advant-ages thereof, will be apparentfrom the foregoing detailed description. It will also be apparent thatwhile we have shown and described our invention in preferred forms,

many changes may be made without departing from thescope of theinvention, as sought to be defined in the following claims.

We claim:

1.' An ultrasonic cleaner comprising a top-loading tank, a transduceraflixed to said tank, a generator for supplying power to drive saidtransducer, a water inlet in said tank, a drain'for said tank, a waterlevel switch set to fill the tank deeply for complete immersion of thearticles to be cleaned, a clock timer driving a series of earnscontrolling electrical circuitry to provide a program of washing andrinsing, and means connecting said circuitry to first cam and circuitportion arranged in circuit with said generator and adapted to energizesaid generator substantially throughout said program, a second camandcircuit portion arranged in circuit with said flow switch to determinethe maximum. depth to which said tank can be filled, and further meansautomatically to drain said tank while continuing to introduce waterinto said tank through said inlet, whereby said circuitry and clocktimer provide a program of washing and rinsing accompanied by ultrasoniccleaning and degassing of water in said tank produced by continuousvibration of said transducer throughout said program.

2. An ultrasonic cleaner comprising a tank, a trans:

Even with medical instruments, the last rinse may be and is a hot rinse,because the blood and skin said circuitry to said generator and waterlevel switch, and providing a first cam and circuit portion arranged incircuit with said generator and adapted to energize said generatorsubstantially throughout said program, a second cam and circuit portionarranged in circuit with said flow switch to determine the maximum depthto which said tank can be filled, and further means automatically todrain said tank while continuing to introduce water into said tankthrough said inlet, whereby said circuitry and level switch and clocktimer provide a program of washing and spraying.

3. An ultrasonic cleaner comprising a tank which opens at' the top fortop loading, a transducer afiixed to said tank, a generator forsupplying power to drive said transducer, a water inlet in said tank, adrain for said tank, a water level switch set to fill the tank deeplyfor complete immersion of the articles to be cleaned, a clock timerdriving a series of cams controlling electrical circuitry to provide aprogram of washing and rinsing, and means connecting said circuitry tosaid generator and water level switch, and providing a first cam andcircuit portion arranged in circuit with said generator and adapted toenergize said generator substantially throughout said program, a secondcam and circuit portion arrangedin circuit with said flow switch todetermine the maximum depth to which said tank can be filled, andfurther means automatically to drain said tank while continuing tointroduce water into said tank through said inlet, whereby saidcircuitry and clock timer provide a program of washing and rinsingaccompanied by ultrasonic cleaning and degassing of water in said tankproduced by continuous vibration of said transducer throughout saidprogram, the water inlet being a spray head mounted for movement into orout of the tank to facilitate top loading, and the pipe leading tosaidspray head being designed to accommodate such movement.

4. An ultrasonic cleaner comprising a tank, a hinged cover for saidtank, a transducer aflixed to said tank, a generator for supplying powerto drive said transducer, a water inlet at the top of the tank, a drainfor said tank, a water level switch for said tank, a clock timer drivinga series of cams controlling electrical circuitry to provide a programof washing and rinsing, means connecting said circuitry to saidgenerator and water level switch, and providing a first cam and circuitportion arranged in circuit with said generator and adaptedto energizesaid generator substantially throughout said program, a second cam andcircuit portion arranged in circuit with said flow switch to determinethe maximum depth to which said tank can be filled, and further meansautomatically to drain said tank while continuing to introduce waterinto said tank through said inlet, whereby said circuitry and levelswitch and clock timer provide a program of washing and rinsing, thewater inlet at the top of the tank being a spray head mounted formovement into or out of the top of the tank, said spray head beingcarried by the cover of the tank, the pipe leading to said spray headacting as the hinge for such movement of the cover and spray head.

5. An ultrasonic cleaner for medical and surgical instruments, saidcleaner comprising a tank, a transducer affixed to said tank, agenerator for supplying power to drive said transducer, a water inlet atthe top of the tank, a drain for said tank, a water level switch set tofill the tank deeply for complete immersion of the articles to becleaned, a clock timer driving a series of cams controlling electricalcircuitry to provide a program of washing and rinsing, means connectingsaid circuitry to said generator and water level switch, and providing afirst cam and circuit portion arranged in circuit with said generatorand adapted to energize said generator substantially throughout saidprogram, a second cam and circuit portion arranged in circuit with saidflow switch to determine the maximum depth to which said tank can befilled, and further means automatically to drain said tank whilecontinuing to introduce water into said tank through said inlet, wherebysaid circuitry and clock timer provide a program of washing and rinsing,a mixer valve assembly ahead of said inlet and having cold and hot waterinlet connections, said assembly comprising solenoid valves and athermostat to maintain a desired warm water temperature so low as not toset blood, and a manually controllable selector to make either thethermostat operative, or the hot water supply alone operative, wherebythe cleaner may be operated with either the aforesaid low temperaturewarm water or much higher temperature hot water as desired.

6. An ultrasonic cleaner comprising a tank, a transducer afiixed to saidtank, a generator for supplying power to drive said transducer, a waterinlet in said tank, a drain for said tank, a water level switch set tofill the tank deeply for complete immersion of the articles to becleaned, a clock timer driving a series of cams controlling electricalcircuitry to provide a program of Washing and rinsing, and meansconnecting said circuitry to said gen erator and water level switch, andproviding a first cam and circuit portion arranged in circuit with saidgenerator and adapted to energize said generator substantiallythroughout said program, a second cam and circuit portion arranged incircuit with saidtflow switch to determine the maximum depth to whichsaid tank can be filled, and further means automatically to drain saidtank while continuing to introduce water into said tank through saidinlet, whereby said circuitry and clock timer provide a program ofwashing and rinsing accompanied by ultrasonic cleaning and degassing ofwater in said tank produced by continuous vibration of said transducerthroughout said program, said clock timer and associated circuitry beingso arranged that the transducer is vibrated during filling of the tankto provide degassing of water in said tank during said filling.

7. An ultrasonic cleaner comprising a tank, a transducer affixed to saidtank, a generator for supplying power to drive said transducer, a waterinlet in said tank, a drain for said tank, a water level switch for saidtank set to fill the tank deeply for complete immersion of the articlesto be cleaned, a clock timer driving a series of cams controllingelectrical circuitry to provide a program of washing and rinsing, andmeans connecting said circuitry to said generator and water levelswitch, and providing a first cam and circuit portion arranged incircuit with saidgenerator and adapted to energize said generatorsubstantially throughout said program, a second cam and circuit portionarranged in circuit with said flow switch to determine the maximum depthto which said tank can be filled, and further means automatically todrain said tank while continuing to introduce water into said tankthrough said inlet, whereby said circuitry and level switch and clocktimer provide a program of washing and rinsing accompanied by ultrasoniccleaning and degassing of water in said tank produced by continuousvibration of said transducer throughout said program, said clock timer,level switch and associated circuitry being so arranged that thetransducer is vibrated continuously throughout the cleaning operation,including filling, washing, and rinsing to provide degassing of water insaid tank commencing with said filling and continuing during saidoperat'orr.

8. An ultrasonic cleaner comprising a tank, a transducer afiixed to saidtank, a generator for supplying power to drive said transducer, a Waterinlet in said tank, a drain for said tank, a water level switch set tofill the tank deeply for complete immersion of the articles to becleaned, a motor driven drain pump for rapid drain, a second'water levelswitch for said tank set at a lower level than said first-named waterlevel switch, a clock timer driving a series of cams controllingelectrical circuitry to provide a program of washing and rinsing, saidclock timer and level switches and associated circuitry beingconnected-to provide a first cam controlled circuit branch includingsaid generator and adapted to energize said generator substantiallythroughout said program, a second cam-controlled circuit branchincluding said first-named water level switch to determine the maximumdepth to which said tank can be filled, and a third circuit branchincluding both of said level switches and the motor of said drain pumpto control operation of said drain pump, and through the cams undercontrol of said clock timer providing a program including a washingperiod of desired duration followed by a fluctuating-level rinse, saidfluctuating-level rinse being provided by a continuous inflowaccompanied by an intermittent operation of said pump to provide drainat a faster rate than the inflow said transducer being vibratedcontinuously throughout the filling of said tank to provide degassing ofwater in said tank during said filling, and throughout said program andsaid fluctuating level rinse.

9. An ultrasonic cleaner comprising a tank, a transducer affixed to saidtank, a generator for supplying power to drive said transducer, a waterinlet in said tank, a drain for said tank, a water level switch set tofill the tank deeply for complete immersion of the articles to becleaned, a motor driven drain pump for rapid drain, a second water levelswitch for said tank set at a lower level than first-named water levelswitch, a clock timer driving a series of cams controlling electricalcircuitry to provide a program of washing and rinsing, said clock timerand level switch and associated circuitry being connected to provide afirst cam-controlled circuit branch including said generator and adaptedto energize said generator substantially throughout said program, asecond cam-controlled circuit branch including said first-named Waterlevel switch to determine the maximum depth to which said tank can befilled, and a third circuit branch including both of said level switchesand the motor of said drain pump to control operation of said drainpump, and through the cams under control of said clock timer providing aprogram including a washing period of desired duration followed by afluctuating-level rinse, said fluctuating-level rinse being provided bya continuous inflow accompanied by an intermittent operation of saidpump to provide drain at a faster rate than the inflow, said circuitrybeing so arranged that the transducer is vibrated throughout the Washingand fluctuating-level rinse to provide continuous degassing of water insaid tank and ultrasonic cleaning of articles which may be in saidwater.

10. An ultrasonic cleaner comprising a tank, a transducer aflixed tosaid tank, a generator for supplying power to drive said transducer, aspray head in said tank, a drain for said tank, a motor driven drainpump for rapid drain, a water level switch for said tank set to fill thetank deeply for complete immersion of the articles to be cleaned, aclock timer driving a series of cams controlling electrical circuitry toprovide a program of washing and rinsing, said clock timer and levelswitch and associated circuitry being connected to provide a firstcam-controlled circuit branch including said generator and adapted toenergize said generator substantially throughout said program, a secondcam-controlled circuit branch including said water level switch todetermine the depth to which said tank can be filled, and a thirdcircuit branch including said water level switch and th emotor of saiddrain pump to control operation of said drain pump, and through the camsunder control of said clock timer providing a program including awashing period of desired duration followed by a fluctuating-levelrinse, said fluctuating-level rinse being provided by a continuous spraythrough said spray head accompanied by an intermittent operation of saidpump to provide drainat a faster rate than the inflow through said sprayhead, said circuitry being so arranged that the transducer is vibratedthroughout the washing and fluctuating-level rinse to provide continuousdegassing of 14 water in said tank and ultrasonic cleaning of articleswhich may be in said water.

ll. An ultrasonic cleaner for medical and surgical instruments, saidcleaner comprising a tank, a transducer aflixed to said tank, agenerator for supplying power to drive said transducer, a water inlet insaid tank, a drain for said tank, a water level switch set to fill' thetank deeply for complete immersion of the articles to be cleaned, amotor driven drain pump for rapid drain, a clock timer driving a seriesof cams controlling electrical circuitry to provide a program of washingand rinsing, a mixer valve assembly ahead of said inlet, and having coldand hot water inlet connections, said assembly comprising solenoidvalves and a thermostat to maintain a desired warm water temperature solow as not to set blood, a manually controllable selector to make-eitherthe thermostat operative or the hot water supply alone operative,whereby the cleaner may be operated with either the aforesaid lowtemperature warm water or much higher temperature hot water as desired,said clock timer and associated circuitry being connected to provide afirst cam-controlled circuit branch including said generator and adaptedto energize said generator substantially throughout said program, asecond cam-controlled circuit branch including said water level switchand said solenoid valves with said selector intervening to determine themaximum depth to which said tank can be filled and the temperature ofthe water therein, and a third circuit branch inoluding said water levelswitch and the motor ofsaid-"drain pump to control operation of saiddrain pump, and through the cams under control of said clock timerproviding a program including a washing period of desired durationfollowed by a fluctuating-level rinse, said fluctuating-level rinsebeing-provided by a continuous inflow accompanied by an intermittentdrain at a faster rate than the inflow. y

12. An ultrasonic cleaner for medical and surgical instruments, saidcleaner comprising a tank, a transducer aflixed to said tank, agenerator for supplying power to drive said transducer, a water inlet insaid tank, a drain for said tank, a motor driven drain pump for rapiddrain, a water level switch for said tank set to fill the tank deeplyfor complete immersion of the articles to be cleaned, a clock timerdriving a series of cams controlling electrical circuitry to provide aprogram of washing and rinsing, a mixer valve assembly ahead of saidinlet and having cold and hot water inlet connections, said assemblycomprising solenoid valves and a thermostat to maintain a desired warmwater temperatureso low as not to set blood, a manually controllableselectorto make either the thermostat operative or the hot water supplyalone operative, whereby the cleaner may be operated with either theaforesaid low temperature warm water or much higher temperature hotwater as desired, said clock timer and level switch and associatedcircuitry being connected toprovide a first cam-controlled circuitbranch including said generator and adapted to energize said generatorsubstantially throughout said program, a second cam-controlled circuitbranch including said water level switch and said solenoid valves withsaid selector intervening to determine the maximum depth to which saidtank can be filled and the temperature of the water therein, and a thirdcircuit branch including said water level switch and the motor of saiddrain pump to control operation of said drain pump, and through the camsunder control of said clock timer providing a program including awashing period of desired duration followed by a fluctuatingdevel rinse,said fluctuating-level rinse being provided by a continuous inflowaccompanied by an intermittent drain at a faster rate than the inflow,said circuitry being so arranged that the transducer is vibratedthroughout the washing and fluctuating-level rinse cycle.

13. An ultrasonic cleaner for medical and surgical instruments, saidcleaner comprising a tank, a transducer affixed to said tank, agenerator for supplying power to drive said transducer, a water inlet insaid tank, a drain for said tank, a motor driven drain pump for rapiddrain, a water level switch for said tank set to fil-l the-tank deeplyfor complete immersion of the articles to be cleaned, a clock timerdriving a series of cams control ling electrical circuitry to provide aprogram of Washing and rinsing, a mixer valve assembly ahead of saidinlet and having cold and hot water inlet connections, said assemblycomprising solenoid valves and a thermostat to maintain a desired warmwater temperature so low as not to set blood, a manually controllableselector to make either the thermostat operative or the hot water supplyalone operative, whereby the cleaner may be operated with either theaforesaid low temperatuer warm water or much higher temperature hotwater as desired, said clock timer and level switch and associatedcircuitry being connected to provide a first cam-controlled circuitbranch including said generator and adapted to energize said generatorsubstantially throughout said program, a second cam oontrolled circuitbranch including said watel level switch and said solenoid valves withsaid selector intervening to determine the maximum depth to which saidtank can be filled and the temperature of the water therein, and a thirdcircuit branch including said water level switch and the motor of saiddrain pump to control operation of said drain pump, and through the camsunder control of said clock timer providing a program including awashing period of desired duration followed by a fluctuating-level rinsewith warm water, said fluctuatinglevel rinse being provided by acontinuous inflow of mixed water accompanied by an intermittent drain ata faster rate than the inflow, said fluctuating-level rinse beingfollowed by a final rinse with only the hot water supply made operative,regardless of the position of the aforesaid selector.

14. An ultrasonic cleaner for medical and surgical instruments, saidcleaner comprising a tank, a transducer affixed to said tank, agenerator for supplying power to drive said transducer, a water inlet insaid tank, a drain for said tank, a motor driven drain pump for rapiddrain, a water level switch for said tank set to fill the tank deeplyfor complete immersion of the articles to be cleaned, a clock timerdriving a series of cams controlling electrical circuitry to provide aprogram of washing and rinsing, a mixer valve assembly ahead of saidinlet and having cold and hot water inlet connections, said assemblycomprising solenoid valves and a thermostat to maintain a desired warmwater temperature so low as not to set blood, a manually controllableselector to make either the thermostat operative or the hot water supplyalone operative, whereby the cleaner may be operated with either theaforesaid low temperature warm water or much higher temperature hotwater as desired, said clock timer and level switch and associatedcircuitry being connected to provide a first cam-controlled circuitbranch including said generator and adapted to energize said generatorsubstantially throughout said program, a second cam-com trolled circuitbranch including said water level switch and said solenoid valves withsaid selector intervening to determine the maximum depth to which saidtank can be filled and the temperature of the water therein, and a thirdcircuit branch including said water level switch and the motor of saiddrain pump to control operation of said drain pump, and through the camsunder control of said clock timer providing a program including awashing period of desired duration followed by a fluctuatinglevel rinsewith warm water, said fluctuating-level rinse being provided by acontinuous inflow of mixed water accompanied by an intermittent drain ata faster rate than the inflow, said fluctuating-level rinse beingfollowed by a final rinse with only the hot Water supply made operative,regardless of the position of the aforesaid selector, said circuitrybeing so arranged that the transducer is vibrated throughout the washingand fluctuatinglevel rinse cycle.

15. An ultrasonic cleaner comprising a. top-loading tank, a transduceraffixed to said tank, a generator for supplying power to drive saidtransducer, a cover for said tank, a water inlet in said tank, a drainfor said tank, a valve to seal said drain, a valve to seal said inlet, alock for the cover of the tank, a steam line connected to said tank, avalve controlling said steam supply, a clock timer driving a series ofcams controlling electrical circuitry for controlling said valves andgenerator to provide a program of washing and rinsing, followed by asterilizing period, and means connecting said generator and valves inrespective circuit branches under control of said cams to provide afirst circuit branch including said generator and adapted to energizesaid generator substantially throughout said program, a second circuitbranch including said valve to seal said drain to provide a drainingportion of said program, and a third circuit branch including all ofsaid valves to provide a sterilizing period whereby said circuitry andclock timer provide a program of washing and rinsing accompanied byultrasonic cleanr ing and degassing of water in said tank produced bycontinuous vibration of said transducer throughout said program, and asterilizing period following said program of washing and rinsing, duringwhich sterilizing period the inlet and drain valves are closed and thesteam valve is opened.

16. An ultrasonic cleaner comprising a toploading tank, a transducerafiixed to said tank, a generator for supplying power to drive saidtransducer, an openable cover for said tank, a spray head at the top ofthe tank, within the cover and secured to said cover, a drain for saidtank, a valve to seal said drain, a valve to seal said inlet, a lock forthe cover of the tank, a steamrline connected to said tank, a valvecontrolling said steam supply, a clock timer driving a series of camscontrolling electrical circuitry for controlling said valves and gen,-erator to provide a program of washing and rinsing, followed by asterilizing period, and means connecting said generator and valves inrespective circuit branches under control of said cams to provide afirstrcircuit branch including said generator and adapted to energizesaid generator substantially throughout said program, a second circuitbranch including said valve to seal said drain to provide a drainingportion of said program, and a third circuit branch including all ofsaid valves to provide a sterilizing period whereby said circuitry andclock timer provide a program of washing and spraying and rinsingaccompanied by ultrasonic cleaning and degassing of water in said tankproduced by continuous vibration of said transducer throughout saidprogram, and a sterilizing period following said program of washing andrinsing, during which sterilizing period the inlet and drain valve areclosed and the steam valve is opened.

17. An ultrasonic cleaner comprising a tank, a transducer aflixed tosaid tank, a generator for supplying power to drive said transducer, awater inlet in said tank, a drain for said tank, a water level switchset to fill the tank deeply for complete immersion of the articles to becleaned, a motor driven drain pump for rapid drain at a rate greaterthan the maximum fill rate through said inlet, a low-level water levelswitch for said tank, a clock timer driving a series of cams controllingelectrical circuitry to provide a program of washing and rinsing, saidclock timer and level switches and associated circuitry being connectedto provide a first cam-controlled circuit branch including saidgenerator and adapted to energize said generator substantiallythroughout said program, a second cam-controlled circuit branchincluding said first-named water level switch to determine the maximumdepth to which said tank can be filled, and a third circuit branchincluding both of said level switches and control for said drain, andthrough said cams under control of said clock timer providing a programincluding a washing period of desired duration followed by afluctuating-level rinse during which said drain pump is intermittently17 operated, said timer and circuitry being so arranged that thetransducer is vibrated throughout the washing period and thefluctuating-level rim-e to provide continuous degassing of water in saidtank and ultrasonic cleaining of articles Which may be in said Water.

2,278,268 Kempton Mar. 31, 1942 Pauly Apr. 25, 1939 10 18 Walter July14, Breckenridge Sept. 22, Tannenberg Jan. 2, Burt-Wells Oct. 14, RingerMay 31, Allen June 9, Thomas Dec. 21, Low Nov. 27,

FOREIGN PATENTS Great Britain Oct. 30,

